math (1126) - Quad: discriminant

got rather scared today when i found out our marks will always be compared to the rest of the grade from now on.

eep -.-

and theres so many more 3u people than us.

gay.

anyway.. besides seeing the proof of how the quadratic formula came to be, we worked with just one simple rule with discriminants.

let y = ax^2 + bx + c

if /\ < 0, y has no real roots, aka doenst collide witht he x-axis

now in terms of taht

if a > 0, and /\ <> 0 for all x values (aka the graph is concave up and above the x-axis)

if a < 0, and /\ < 0, the function is negative definite, and y < 0 for all x values (aka the graph is concave down and below the x-axis